This application claims priority to Japanese Patent Application Number JP2002-239797 filed Aug. 20, 2002, Japanese Patent Application Number JP2002-320862 filed Nov. 5, 2002, and Japanese Patent Application Number JP2002-334220 filed Nov. 18, 2002, all of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a technology in which, in a liquid ejecting device having a head including at least one liquid ejecting portion and in a liquid ejecting method using a head including at least one liquid ejecting portion, a current-mirror circuit is used to deflect liquid ejected from each liquid ejecting portion, and to a technology for simplifying (downsizing) entire circuit structure.
2. Description of the Related Art
Inkjet printers have been conventionally known as a type of liquid ejecting device having heads which each include a plurality of liquid ejecting portions arranged in parallel. A thermal method that uses thermal energy to eject ink is known as one of ink ejecting methods for inkjet printers.
In an example of a head structure using the thermal method, ink in an ink cell is heated by a heating element (heating resistor) disposed in the ink cell to produce bubbles in the ink on the heating element, and the energy of the generation of the bubbles ejects the ink. A nozzle is formed in the upper side of the ink cell. When the bubbles are produced in the ink in the ink cell, the ink is ejected from the ejecting outlet of the nozzle.
From the viewpoint of head structure, there are two methods, a serial method and a line method. In the serial method, an image is printed by moving a head in the width direction of printing paper. In the line method, many heads are arranged in the width direction of printing paper to form a line head for the width of the printing paper.
FIG. 21 is a plan view showing a line head 10 of the related art. Although FIG. 21 shows four heads 1 (Nxe2x88x921, N, N+1, and N+2), a larger number of heads 11 are actually arranged in parallel.
In each head 1, a plurality of (normally, approximately hundred units of) ink cells, heating elements, and nozzles 1a as described above are arranged in parallel. The line head 10 is formed by arranging the heads 1 in a predetermined direction (the width direction of printing paper).
Two adjacent heads 1 in the predetermined direction are disposed on one side and the other side across an ink-flow pass 2 extending in the predetermined direction, and the head 1 on the one side and the head 1 on the other side are alternately disposed so that both opposes each other, that is, nozzles 1a can oppose each other. Between the adjacent heads 1, the pitch of the nozzles 1a is consecutively maintained, as shown in the detail of portion A in FIG. 21 (see Japanese Unexamined Patent Application Publication No. 2002-36522).
The related art shown in FIG. 18 has the following problems.
When ink is ejected from the printer-head chips 1, it is ideal that the ink is ejected perpendicularly to the ejection surface of the printer-head chips 1. However, various factors may cause a case in which an angle at which the ink is ejected is not perpendicular.
For example, when a nozzle sheet having the nozzles 1a formed thereon is bonded to a head chip including the ink cells and the heating elements, the problem is positional shifting of the nozzle sheet. When the nozzle sheet is bonded so that the center of the nozzles 1a is positioned in the center of the ink cells and the heating elements, the ink is ejected perpendicularly to the ink ejection surface (the nozzle sheet surface). However, if positional shifting occurs between the central axis of the ink cells and the heating elements and the central axis of the nozzle 1a, the ink cannot be ejected perpendicularly to the ejection surface. In addition, positional shifting can be caused by a difference in coefficient of thermal expansion between the nozzle sheet, and the ink cells and the heating elements.
When such a difference in angel of ejection of ink occurs, it appears as a shift in pitch of delivered ink in the case of the serial method. In the case of the line method, the difference appears as a positional shift between two heads 1, in addition to the shift in pitch of delivered ink.
FIGS. 22A and 22B are a sectional view and plan view showing printing by the line head 10 shown in FIG. 21. In FIGS. 22A and 22B, assuming that printing paper P is fixed, the line head 10 does not move in the width direction of the printing paper P, and performs printing while moving from top to bottom of the plan view (FIG. 22B).
In the section view in FIG. 19A, among the line head 10, three heads 1, that is, the N-th head 1, the (N+1)-th head 1, and the (N+2)-th head 1 are shown.
As shown in the section view in FIG. 22A, in the N-th head 1, ink is slantingly ejected in the left direction as is indicated by the left arrow. In the (N+1)-th head 1, ink is slantingly ejected in the right direction as is indicated by the central arrow. In the (N+2)-th head 1, ink is perpendicularly ejected without a shift in angle of ejection as is indicated by the right arrow.
Accordingly, in the N-th head 1, the ink is delivered, being off to the left from a reference position, and in the (N+1)-th head 1, the ink is delivered, being off to the right from the reference position. Thus, between both, the ink in the N-th head 1 and the ink in the (N+1)-th head 1 are delivered to opposite directions. As a result, a region in which no ink is delivered is formed between the N-th head 1 and the (N+1)-th head 1. In addition, the line head 10 is only moved in the direction of the arrow in the plan view in FIG. 19B without being moved in the width direction of the printing paper P. This forms a white stripe B between the N-th head 1 and the (N+1) head 1, thus causing a problem of deterioration in printing quality.
Similarly to the above case, in the (N+1)-th head 1, the ink is delivered, being off to the right from the reference position. Thus, the (N+1)-th head 1 and the (N+2)-th head 1 have a common region in which the ink is delivered. This causes a discontinuous image and a stripe C which has a color thicker than the original color, thus causing a problem of deterioration in printing quality.
When such a shift in a position to which ink is delivered occurs, the degree to which a stripe looks noticeable depends on an image to be printed. For example, since a document or the like has many blank portions, a stripe will not look noticeable if it is formed. Conversely, in the case of printing a photograph image in almost all the portions of printing paper, if a slight strip is formed, it will look noticeable.
It is an object of the present invention to provide a liquid ejecting device having a head including a liquid ejecting portion or liquid ejecting portions arranged in parallel and a liquid ejecting method using a head including a liquid ejecting portion or liquid ejecting portions arranged in parallel, wherein the direction of liquid ejected from each liquid ejecting portion is controlled.
The present invention provides a circuit form that is particularly suitable for the case of incorporating means of deflecting ejected liquid with a head in technology in Japanese Patent Application Nos. 2002-112947 and 2002-161928 which have already been filed by the Assignee of the present Application. Also, in the present invention, by simplifying (downsizing) the entire circuit, the means can be used even for a head having a resolution of 600 dpi or higher.
According to a first aspect of the present invention, a liquid ejecting device having a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction. The liquid ejecting device includes a main operation controller which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell, performs control so that the liquid is ejected from the nozzle, and a sub operation controller provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a second aspect of the present invention, a liquid ejecting device having a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction. The liquid ejecting device includes a main operation controller which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell, performs control so that the liquid is ejected from the nozzle, and a sub operation controller provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled to change with respect to a direction in which liquid is ejected by the main operation controller.
According to a third aspect of the present invention, a liquid ejecting device having a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction. The liquid ejecting device includes a main operation controller which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell, performs control so that the liquid is ejected from the nozzle, and a sub operation controller provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a fourth aspect of the present invention, a liquid ejecting device having a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction. The liquid ejecting device includes a main operation controller which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell, performs control so that the liquid is ejected from the nozzle, and a sub operation controller provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled to change to the predetermined direction with respect to a direction in which liquid is ejected by the main operation controller.
According to the present invention, by incorporating a main operation controller and a sub operation controller including a current-mirror circuit, for example, in a digital circuit, the formed integrated-circuit structure which is suitable for a head is obtained.
According to a fifth aspect of the present invention, a liquid ejecting method using a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and at least one current-mirror circuit is connected to a junction of the energy generating elements, and the liquid from the nozzle is controlled so as to be ejected in at least two different directions by using a main operation-control step which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell without using the at least-one current-mirror circuit, performs control so that the liquid is ejected from the nozzle, and a sub operation-control step in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a sixth aspect of the present invention, a liquid ejecting method using a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and at least one current-mirror circuit is connected to a junction of the energy generating elements. The liquid from the nozzle is controlled so as to be ejected in at least two different directions by using a main operation-control step in which, by supplying equal amounts of currents to the connected energy generating elements in the liquid cell without using the at least one current-mirror circuit, the liquid is controlled to be ejected from the nozzle, and a sub operation-control step in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a seventh aspect of the present invention, a liquid ejecting device having a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and the liquid ejecting device includes a control unit provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to an eighth aspect of the present invention, a liquid ejecting device having a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and the liquid ejecting device includes an ejection deflecting unit provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the liquid ejected from the nozzle is deflected in the predetermined direction and the opposite direction thereto.
According to the present invention, by controlling the amounts of currents flowing in energy generating elements to differ, a difference is set in the time required for generating bubbles by the energy generating elements. Based on the difference, the direction of ejected liquid is controlled and is also changed. By deflecting ejected liquid, a position to which the liquid is delivered can be changed.
According to a ninth aspect of the present invention, a ninth aspect of the present invention, a liquid ejecting device having a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and the liquid ejecting device includes a control unit provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a tenth aspect of the present invention, a liquid ejecting device having a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and the liquid ejecting device includes an ejection deflecting unit provided for each of the liquid ejecting portions which includes at least one current-mirror circuit connected to a junction of the energy generating elements, and in which, by using the current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the liquid ejected from the nozzle is deflected in the predetermined direction and the opposite direction thereto.
According to an eleventh aspect of the present invention, a liquid ejecting device using a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and at least one current-mirror circuit is connected to a junction of the energy generating elements, and by using the at least one current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a twelfth aspect of the present invention, a liquid ejecting method using a line head formed by a plurality of heads arranged in a predetermined direction is provided. The heads each are formed by a plurality of liquid ejecting portions arranged in parallel in the predetermined direction. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, and a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the energy generating elements are connected in series to one another and are arranged in parallel in the predetermined direction, and at least one current-mirror circuit is connected to a junction of the energy generating elements, and by using the at least one current-mirror circuit to allow a current to flow into or to flow from the junction of the energy generating elements, the amount of a current supplied to each of the energy generating elements is controlled and the direction of the liquid ejected from the nozzle is controlled.
According to a thirteenth aspect of the present invention, a liquid ejecting device having a head including a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portions each include a liquid cell for containing liquid, at least one energy generating element provided in the liquid cell which produces a bubble in response to the supply of energy, a nozzle for ejecting the liquid in the liquid cell by using the bubble produced by the at least one energy generating element. In the liquid cell, the heating elements are connected in series to one another and are arranged in parallel in the predetermined direction. The liquid ejecting device includes a main operation controller which, by supplying equal amounts of currents to all the heating elements, performs control so that the liquid is ejected from the nozzle, and a sub operation controller which supplies currents to all the heating elements in the liquid cell, and which, by setting a difference between the amount of the current flowing in at least one of the heating elements and the amount of the current flowing in another one of the heating elements, performs control based on the difference so that the ejected liquid is deflected in the predetermined direction with respect to a direction in which liquid is ejected by the main operation controller. The liquid ejecting portions arranged in parallel are divided into a plurality of blocks so that groups of the liquid ejecting portions respectively belong to the blocks, and the liquid ejecting device includes a dedicated circuit provided for each of the liquid ejecting portions, and a common circuit provided for each of the blocks which is shared by the liquid ejecting portions belonging to the block, and which includes at least part of one of the main operation controller and the sub operation controller and ejects liquid from one of the liquid ejecting portions belonging to the block.
According to the present invention, when liquid is ejected, one liquid ejecting portion can be prevented from affecting another liquid ejecting portion. In the case of such control, at least part of a circuit for ejecting liquid may be provided a single common circuit for a plurality of liquid ejecting portions. This enables circuit simplification for the entire head.
According to the present invention, by using a plurality of energy generating elements and a current-mirror circuit to allow a current to flow into or from a junction of the energy generating elements so that the amounts of currents flowing in the energy generating elements differ, a difference can be set in bubble producing time between energy generating elements. Accordingly, based on the difference, the direction of ejected liquid can be controlled. More specifically, it can be changed (shifted from perpendicularity with respect to a plane of ejection). By deflecting ejected liquid, a position to which the liquid is delivered can be changed.
Therefore, for example, if there is a shift in a position to which liquid ejected from a particular liquid ejecting portion is delivered, the shift can be corrected.
Moreover, according to the present invention, in the case of incorporating means of changing ejected liquid with a head, simplification (downsizing) of the entire circuit enables the means to be used even for a high resolution head.